Is there a way to get rid of this banner for god sake? I like Maxthon so much, it's my favorite browser, it has only I need, it's fast and dont have lags.

That happens because the core of maxthon is already something old, 61.x. For example with the latest beta version of maxthon of the series 5.3.8.x, that notice will not appear, since this version has nucleus 69.x (if I remember correctly.

To partially solve this warning, as you have done, is editing the User-Agent. In this thread below you will have the right one.

and after that I tried other.. Truncated Versions like the title said '' For Windows 10:Mozilla/5.0 (compatible; Windows NT 10.0; WOW64; IA64; en) AppleWebKit/599.0+ (KHTML, like Gecko) Maxthon/5.2.7 Chrome/73.0.3683.103 QupZilla/2.2.6 ''